Improvements to documentation, logging, connection error handling behavior, and container queue management

Validate that the configuration file grants middleboxes the context access they require for their activities

Also improve logging of container contents, now taking into account container accessibility.

- Fixed off-by-one in template processing that resulted in
  minimum-size templates being treated as literal strings

- Enable time and size-based read queue draining

- Remove old pinpong.ucl file, correct template documentation in
  everything.ucl